Azo dye and process of making same.



. water.

, UNITED STATES PATENT OFFICE.

WILI-IELM HERZBERG AND MAX BONUS, OF BERLIN, GERMANY, ASSIGNORS TOACTIEN GESELLSCHAFT FT J'R ANILIN FABRIKATION, 0F BERLIN, GERMIANY.

AZO DYE AND PROCESS OF MAKING SAME.

No Drawing.

berger Ufer 36 have invented certain new and useful Improvements in NewAzo Coloring-Matters and Processes of Making Same, of which thefollowing is a specification.

We have found that by combining the diazo compound of an aromatic aminof the general formula:

in which formula X represents a halogen atom, with beta-naphthol, newmonoazo dyestuffs are obtained which possess, generally speaking, a verybrilliant red tint and are es pecially adapted for the manufacture ofpigment-colors or lakes. The new colors or lakes are obtained from thenew dyestuffs in the manner usual for production of lakes and possess,in addition to a brilliant tint, a very great fastness to light;furthermore, they are totally insoluble in water, in alcohol and in oil.The manufacture of lakes may also be combined with the production of thedyestuffs for instance by mixing the solution of the beta-naphthol witha suitable lake substratum, such as for instance aluminium hydrate, andadding the respective diazo-solution to the mixture;

The following example illustrates our invention, the parts being byweight: 18.6 parts of 3-chloro-5-nitro-2-amino-l-methylbenzene arebrought to a fine suspension with water in mixture with 27 parts ofhydrochloric acid of 20 B. specific gravity, whereupon an aqueoussolution of 7 parts of sodium nitrite is added while stirring well. Whenthe nitrite is totally absorbed the solution is filtered if necessary inorder to remove the substances not dissolved and the solution is allowedto run into a fine suspension of 14.4 parts of beta-naphthol with Theformation of the dyestufi" occurs at once and is complete after a shortSpecification of Letters Patent.

Application filed January 3, 1910.

Patented Apr. 12, 1910.

Serial No. 538,155.

time. The mass is then drained and thoroughly washed with water. Inorder to use the dyestuff for industrial purposes it may be directlyused in the form of a paste as obtained above; or this paste may bedried and finely pulverized.

The new dyestuff as above obtained forms in the dry state an intense andbrilliant red powder which is insoluble in water, in alcohol at ordinarytemperature and in boiled linseed oil (linseed oil varnish). Alcohol onboiling dissolves the dyestuff in very small proportion the solutionassuming a. yellow color. By adding concentrated sodalye to thepulverized dyestuif the powder assumes a brown color which on boilingturns to black the solution assuming a yellow coloration. Dilutesoda-lye does not alter the tint of the powder, whereas on boiling itbecomes a little browner. In concentrated sulfuric acid the dyestuifdissolves to a bluered solution which on the addition of ice separatesred-orange flakes.

It is obvious to those skilled in the art that our invention is notlimited to the foregoing example or to the details given therein. Ofcourse instead of the chloro compound used in the above example thecorrespond ing bromo derivative may be employed. Furthermore it may bestated that the production of the dyestuif may be combined with themanufacture of a color lake, for instance by adding a suitable lakesubstratum to the finely divided beta-naphthol into which mixture isthen introduced the diazo solution prepared from the respective halogenderivative of para-nitro-orthotoluidin.

Having now described our invention and the manner in which it may beperformed, what we claim is,

1. The hereinbefore-described new monoazo-dyestuffs having the generalcompositi on3-halogen-5-nitro-2-amino-1-methylbenzene-azo-beta-naphthol, which newdyestufi's may be obtained by combining the diazo-compound of a3-halogen-5-nitro-2- amino-l-methylbenzene with beta-naphthol, these newdyestuifs being in the dry and pulverized shape intense and brilliantred powders, which are insoluble in water and in boiled linseed-oil(linseed-oil varnish) and are very sparingly soluble in alcohol, whereasthey dissolve in concentrated sulfuric acid to a blue-red solution fromwhich soluwhich may be obtained by diazotizing 3-chloro-5-nitro-2-amino-l-methylbenzene and combining the diazo-compoundthus ob tained with beta-naphthol, this new dyestufi being in the dryand pulverized shape an intense and brilliant red powder which isinsoluble in water and in boiled linseedoil (linseed-oil varnish) and isvery sparingly soluble in alcohol to a yellow-colored solution, andwhich powder by adding concentrated soda-lye assumes a brown color whichon boilin turns to black, the solution assuming a yellow coloration,whereas dilute soda-lye does not alter the tint of the powder, but thepowder on boiling becoming a little browner, this (1 estufi dissolvingin concentrated sulfuric acid to a blue-red solution, which on theaddition of ice separates red-orange flakes, and this new azodyestufi'bein especially ada ted for the manufacture of color-lakes, w ich newazo-dyestufi' by the action of a strong reducing agent (stannous chloridin combination with hydrochloric acid) is split up, thus yielding metachloro para toluylenediamin besides ortho-aminonaphthol.

In testimony whereof we have hereunto set our hands in presence of twosubscribing witnesses.

WILHELM HERZBERG. MAX BONUS. Witnesses:

HENRY HAsrER, WOLDEMAR HAUPT.

